Methyl-5-(4)-carbamoylmethylimidazole-4-(5)-carboxylate (I) and phosphoryl chloride are refluxed for 1 h, cooled, titurated with petroleum ether (30-60 C) and diethyl ether. Ice, followed by aqueous ammonia solution, is added to give a pH of 6.0. The solvent is then removed in vacuuo and the solid extracted with hot ethyl acetate. After drying with magnesium sulfate, the ethyl acetate is removed in vacuuo and the straw-colored methyl-5-(4)-cyanomethylimidazole-4-(5)-carboxylate (II) is recrystallized from water. Hydrazine hydrate is refluxed with (II), giving a precipitate of 5-amino-6-hydrazino-1,5-dihydroimidazol-[4,5-c]pyridin-4-one (III). A solution of (III) in boiling water is treated with Raney Nickel catalyst and refluxed. Filtration and concentration of the filtrate give, upon standing overnight, yellow crystals of 3-deazaguanine.

Methyl-5-(4)-carbamoylmethylimidazole-4-(5)-carboxylate (I) and phosphoryl chloride are refluxed for 1 h, cooled, titurated with petroleum ether (30-60 C) and diethyl ether. Ice, followed by aqueous ammonia solution, is added to give a pH of 6.0. The solvent is then removed in vacuuo and the solid extracted with hot ethyl acetate. After drying with magnesium sulfate, the ethyl acetate is removed in vacuuo and the straw-colored methyl-5-(4)-cyanomethylimidazole-4-(5)-carboxylate (II) is recrystallized from water. Hydrazine hydrate is refluxed with (II), giving a precipitate of 5-amino-6-hydrazino-1,5-dihydroimidazol-[4,5-c]pyridin-4-one (III). A solution of (III) in boiling water is treated with Raney Nickel catalyst and refluxed. Filtration and concentration of the filtrate give, upon standing overnight, yellow crystals of 3-deazaguanine.